中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 22 No. 4 April 2012 |
（1. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085, China;
2. School of Materials Science and Engineering, Beijing University of Science and Technology,
Beijing 100083, China）
Abstract:The corrosion behaviors of Sn−0.75Cu solder and Sn−0.75Cu/Cu joint in 3.5% NaCl (mass fraction) solution were studied by potentiodynamic polarization test and leaching measurement. The polarization curves indicated that the corrosion rate of Sn−0.75Cu solder was lower than that of Sn−0.75Cu/Cu joint. The morphology observation and phase composition analysis on the corroded product at each interesting potential suggested that Sn3O(OH)2Cl2 formed on the surface of Sn−0.75Cu solder at active dissolution stage. As the potential increased from active/passive transition stage, all the surface of Sn−0.75Cu solder was covered by the Sn3O(OH)2Cl2 and some pits appeared after the polarization test. Compared to the Sn−0.75Cu solder alloy, much more Sn3O(OH)2Cl2 formed at active dissolution stage and the pits with bigger size were observed after polarization test for the Sn−0.75Cu/Cu solder joints. The leaching test confirmed that the faster electrochemical corrosion rate resulted in the larger amount of Sn released from the Sn−0.75Cu/Cu solder joints.
Key words: Sn−0.75Cu solder; Sn−0.75Cu/Cu joint; corrosion; potentiodynamic polarization; leaching behavior; corroded products
